Analytical Modeling of Electrostatic Characteristics of Enhancement Mode GaN Double Channel HEMT

Abstract

In this paper, the electrostatic characteristics of enhancement mode GaN double channel MOS-HEMT has been investigated. A polynomial analytical expression establishing a relationship between the Fermi level and the two-dimensional electron gas density has been developed for this device for the first time. This analytical expression has been utilized to develop a relationship between sheet carrier density and applied gate voltage. A self-consistent simulation incorporating quantum mechanical effect has been carried out to obtain the charge density profile and capacitance-voltage profile. The variation of conduction band profile with the variation of gate voltage has been inspected. The impact of variation of GaN channel thickness on the conduction band profile and the charge density profile is also explored. The comparison of results obtained from the analytical model and simulation confirms that the analytical model produces satisfactory result in both subthreshold and saturation region. We have extracted threshold voltage which corroborates enhancement mode operation of the device. Finally it has been showed that our results are congruent with published results found in the literature.